Chip Sets Boost Performance

Intel adds support for hyperthreading, faster bus and memory speeds.

Intel Corp. last week announced four desktop chip sets designed to support future processors that will feature its hyperthreading technology and bolster PC performance through faster system bus and memory speeds.

The new chip sets—the 845GE, 845PE, 845GV and upgraded 850E—support hyperthreading, which will be introduced in the Pentium 4 line this quarter with the release of a 3.06GHz version of the chip.

Hyperthreading is a technology Intel developed that can boost PC performance up to 30 percent by enabling a single chip to work like two virtual chips. The feature is currently offered only in Intel Xeon processors targeted for use in workstations and servers.

The Intel 845GE chip set includes an increased 266MHz graphics clock speed for its Intel Extreme Graphics engine and either a 533MHz or 400MHz system bus—depending on the processor—as well as support for 333MHz DDR (double data rate) SDRAM (synchronous dynamic RAM).

The Intel 845PE supports 333MHz DDR SDRAM as well as an add-on graphics card with an AGP 4X slot. The 845GV offers support for 266MHz DDR SD-RAM with either a 533MHz or 400-MHz system bus.

While the upgrade to 333MHz DDR SDRAM from 266MHz DDR SD-RAM on the 845GE and 845PE chip sets should increase graphics performance, the memory upgrade may result in slower system performance while running some programs, said Kevin Krewell, an analyst with In-Stat/MDR, in Sunnyvale, Calif.

The potential problem is that the speed of the processors front-side bus is out of sync with that of the memory. The 533MHz front-side bus of Intels Pentium 4 processor is a quadruple-pumped bus running at a base clock rate of 133MHz, while the 333MHz DDR SDRAM is a double-pumped bus with a base clock rate of 166MHz, Krewell said.

"The graphics and main memory are running at 166MHz, but the processor is running at 133MHz, so they are out of sync, and because of that, theres extra buffering," Krewell said. "That extra buffering sometimes increases memory latency. As a result, the DDR 333MHz solution may do better graphics, but it might do a little bit worse on some benchmarks."

The upgraded 850E, Intels top chip set designed for use with the companys fastest processors, now supports dual-channel 1,066MHz RDRAM (Rambus DRAM), the fastest RDRAM technology available. The chip set also offers a 533MHz system bus. The chip set is targeted for power PC users and is suitable for gaming and encoding and editing digital film and music.

The 850E is the last chip the Santa Clara, Calif., company has on its road map that will support RDRAM, a technology it predicted would dominate the market when it released its first Rambus-based design in 1999 but which has been largely relegated to a niche market by the emergence and widespread adoption of DDR SDRAM.

The chip sets are priced at $28 for the 845GV, $34 for the 845PE, $37 for the 845GE and $40 for the 850E. Prices are based on 1,000-unit shipments.